| 1. |
- Cichon, M., et al.
(author)
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Genetic and environmental variation in immune response of collared flycatcher nestlings
- 2006
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In: Journal of Evolutionary Biology. - : Wiley. - 1010-061X .- 1420-9101. ; 19:5, s. 1701-1706
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Journal article (peer-reviewed)abstract
- This paper aims at partitioning genetic and environmental contribution to the phenotypic variance in nestling immune function measured with the hypersensitivity test after inoculation with phytohaemagglutinin. A cross-fostering experiment with artificial enlargement of some broods was conducted. Variation in nestling immune response was related to their common origin, which suggests heritable component of cell-mediated immunity. A common rearing environment also explained a significant part of variation. However, deterioration of rearing conditions as simulated by enlargement of brood size did not affect nestling immunocompetence, although it affected nestling body mass. Variation in body mass explained some of the variation in immune response related to rearing environment, which means that growth is more sensitive to the shifts in rearing conditions than the development of immune function. Heritable variation in immune response suggests that there should be potential for selection to operate and the micro evolutionary changes in immunity of flycatcher nestlings are possible.
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| 2. |
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| 3. |
- Pitala, Natalia, et al.
(author)
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Nestling immune response to phytohaemagglutinin is not heritable in collared flycatchers
- 2007
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In: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 3:4, s. 418-421
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Journal article (peer-reviewed)abstract
- The response to intradermally injected phytohaemagglutinin (PHA-response) is a commonly used quantification of avian immunocompetence (the ability to resist pathogens). Parasite-mediated sexual selection requires heritable immunocompetence, but evidence for heritability of PHA-response in birds largely stems from full-sib comparisons. Using an animal model approach, we quantified the narrow-sense heritability of PHA-response in 1626 collared flycatcher (Ficedula albicollis) nestlings from 332 families, most of which were cross-fostered. Nestling PHA-response was not significantly heritable (h2=0.06±0.10), but was subject to non-heritable nest-of-origin effects (10% of variation). Our findings illustrate that full-sib comparisons of immunological measures may lead to an inflated estimate of heritability and also reveal a limited role of nestling PHA-response for sexual selection in this population.
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| 4. |
- Sendecka, Joanna, et al.
(author)
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Age-dependent reproductive costs and the role of breeding skills in the Collared flycatcher
- 2007
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In: Acta Zoologica. - : Wiley. - 0001-7272 .- 1463-6395. ; 88:2, s. 95-100
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Journal article (peer-reviewed)abstract
- This study addressed whether there are any age-related differences in reproductive costs. Of especial interest was whether young individuals increased their reproductive effort, and thereby their reproductive cost, as much as older birds when brood size was enlarged. To address these questions, a brood-size manipulation experiment with reciprocal cross-fostering of nestlings of young and middle-aged female Collared flycatchers, Ficedula albicollis, was performed on the Swedish island of Gotland. Nestlings' body mass, tarsus length and survival were recorded to estimate the parental ability and parental effort of the experimental female birds. Female survival and clutch size were recorded in the following years to estimate reproductive costs. We found that middle-aged female flycatchers coped better with enlarged broods than younger females or invested more in reproduction. In the following year, young female birds that had raised enlarged broods laid smaller clutches than the females from all the other experimental groups. This result shows that the young female birds pay higher reproductive costs than the middle-aged females. Both young and middle-aged female flycatchers seemed to increase their reproductive effort when brood size was increased. However, such an increase resulted in higher reproductive costs for the young females. The difference in reproductive costs between birds of different ages is most likely a result of insufficient breeding skills of the young individuals.
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| 5. |
- Sendecka, Joanna, 1975-
(author)
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Age, Longevity and Life-History Trade-Offs in the Collared Flycatcher (Ficedula albicollis)
- 2007
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Doctoral thesis (other academic/artistic)abstract
- Age is often a neglected factor in ecological studies. However, age-related changes in reproduction and survival of organisms may strongly influence population dynamics. The Gotlandic population of collared flycatchers is a perfect system for studying age-related changes in the wild, as the exact age and reproductive history of most individuals is known. Collared flycatchers (Ficedula albicollis) on Gotland show the typical pattern of age-related changes in survival and reproductive success; both factors show an increase early in life and a decrease late in life. This thesis presents a broad study not only of age-related patterns of reproduction and immunity, but also proposes the mechanisms driving these patterns. My results show that in addition to survival probability and reproductive performance, reproductive costs and life-history trade-offs also change with progressing age. There is a significant increase in reproductive performance at the population level during first years of life which result from selection against low quality phenotypes. On the individual level this pattern is best explained by an optimization of reproductive effort. However, high quality individuals have higher reproductive success as early as their first breeding event and are long-lived. Thus, they seem to adopt a different strategy than lower quality, short-lived individuals. Differences in individual quality seem to be shaped by the developmental conditions experienced as nestlings. Fledglings with longer tarsi, but lower body mass become long-lived, high quality adults. Young individuals breeding for first time pay higher costs of reproduction. They also express a limited ability to reduce these costs by breeding in high quality territories when compared to middle-aged individuals. Young individuals seem to invest more into self-maintenance, whereas old individuals reduce the level of self-maintenance (measured as immune response) and redistribute their investment towards reproduction. Thus, old individuals are limited in their ability to reduce reproductive costs under favorable conditions, especially as they also senesce, which pattern is also shaped by individual quality. Variation in individual quality appears to have an strong effect on age-related survival probability, reproductive performance, reproductive costs, and even life-history decisions. Therefore, taking this factor into account in studies of life-history patterns is necessary to obtain reliable results.
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| 6. |
- Tschirren, Barbara, et al.
(author)
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Heritable Variation in Maternal Yolk Hormone Transfer in a Wild Bird Population
- 2009
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In: American Naturalist. - : University of Chicago Press. - 0003-0147 .- 1537-5323. ; 174:4, s. 557-564
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Journal article (peer-reviewed)abstract
- Differential reproductive investment by the mother can critically influence offspring development and phenotype, and strong selection is therefore expected to act on such maternal effects. Although a genetic basis is a prerequisite for phenotypic traits to respond to selection and thus to evolve, we still know very little about the extent of heritable variation in maternal effects in natural populations. Here, we present the first estimates of intrafemale repeatability across breeding seasons and estimates of heritability of hormone-mediated maternal effects in a wild population of collared flycatchers (Ficedula albicollis). We found that maternal yolk testosterone (T) concentrations, yolk mass, and egg mass were moderately to highly repeatable within females across years, whereas intrafemale consistency of maternal yolk androstenedione (A4) deposition was low yet statistically significant. Furthermore, maternal yolk T transfer, yolk mass, and egg mass were significantly heritable, whereas yolk A4 transfer was not. These results strongly suggest that two major maternal yolk androgens are differentially regulated by genes and the environment. Selection on heritable variation in maternal yolk T deposition has the potential to shape the rate and direction of phenotypic change in offspring traits and can thereby accelerate or impede the response to selection in natural populations.
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